(1) Background: Endoscopic colorectal stenting with high technical success and safety is essential in discussing the oncological outcomes for the management of malignant colorectal obstruction. Mechanical properties of self-expandable metal stents are usually considered to affect clinical outcomes. (2) Methods: A multicenter, prospective study was conducted in Japan. A self-expandable metal stent with low axial force was inserted endoscopically. The primary endpoint was clinical success, defined as the resolution of symptoms and radiological findings within 24 h. Secondary endpoints were technical success and adverse events. Short-term outcomes of 7 days were evaluated in this study. (3) Results: Two hundred and five consecutive patients were enrolled. Three patients were excluded, and the remaining 202 patients were evaluated. The technical and clinical success rates were 97.5% and 96.0%, respectively. Major stent-related adverse events included stent migration (1.0%), insufficient stent expansion (0.5%), and stent occlusion (0.5%). No colonic perforation was observed. There were two fatal cases (1%) which were not related to stent placement. (4) Conclusions: The placement of self-expandable metal stents with low axial force is safe with no perforation and showed high technical and clinical success rates in short-term outcomes for the management of malignant colorectal obstruction.
298 Background: Smoking is recognized as a risk factor for pancreatic cancer, but its associations with prognosis are not fully elucidated. Smoking was associated with poor outcomes in colon cancer, especially in patients with K-ras mutation (J Clin Oncol. 2013;31:2016-23). Therefore, we conducted this retrospective analysis of the associations of K-ras mutation, smoking and prognosis in patients with pancreatic cancer. Methods: Patients with pancreatic cancer who received surgery or chemotherapy at the University of Tokyo Hospital were retrospectively studied. The prognosis of patients with mutant and wild K-ras were compared. Overall survival was evaluated using Kaplan-Meier methods and compared by long-rank test. Cox regression models were used to calculate hazard ratios (HRs) to evaluate the prognostic factors in patients with pancreatic cancer with mutant K-ras or wild K-ras. Results: Between January 2009 and August 2013, K-ras mutation analysis was evaluated in 187 patients (47 surgical resection and 140 chemotherapy). K-ras mutation was detected in 74.3%. The rates of current-, ex- and never-smokers were 18.2%, 31.6% and 50.3%, respectively. In patients with mutant K-ras, the rate of male gender (46.0% vs. 29.0%), presence of distant metastasis (50.4% vs. 31.3%) and median CA19-9 (374 U/mL vs. 136 U/mL) were significantly higher than that in patients with wild K-ras. The rate of ever smokers (current- and ex-smokers) did not differ significantly (48.2% in mutant K-ras vs. 56.3% in wild K-ras, p=0.403). Median survival time (MST) was 16.7 (95%CI, 11.9-21.8) months in patients with mutant K-ras, compared with 20.3 (95%CI, 15.8-34.6) in patients with wild K-ras (p=0.193). Meanwhile, MST was 22.2 (95%CI, 16.9-27.9) vs. 14.8 (95%CI, 9.1-19.4) months in patients with and without smoking (p=0.024). After adjustment by age, gender, performance status, CA19-9 and treatment, HRs of smoking were 1.96 (95%CI, 1.06-3.68, p=0.032) in patients with mutant K-ras, but the association was not significant in patients with wild-K-ras (HR 1.35 [95%CI, 0.37-5.28], p=0.653). Conclusions: As previously reported in colon cancer, smoking was associated with poor prognosis in pancreatic cancer with K-ras mutation.
Abstract Background In Japan, microsatellite instability (MSI) testing for solid tumors was introduced in clinical practice in December 2018. Although immune checkpoint inhibitors (ICIs) are established standards of care for patients with MSI‐high tumors, the status of implementing MSI testing in clinical practice remains unclear. Methods We retrospectively reviewed the medical records of patients with solid tumors who underwent MSI testing between January 2019 and December 2020 at our institution. Results In total, 1,052 MSI tests were performed in 1,047 patients. Regardless of specimen volume and condition, the MSI status was successfully determined in 1,041 (99.0%) tests, encompassing 27 tumor types (microsatellite stable [MSS] or MSI‐low: n = 991 [95.2%] and MSI‐high: n = 50 [4.8%]). Patients whose specimens were fixed with 20% neutral buffered formalin (NBF) and who had specimens with prolonged storage (98.4% and 95.4%) showed lower success rates than those whose specimens were fixed with 10% NBF and who had specimens with nonprolonged storage (100.0% and 99.6%), respectively. The prolonged turnaround time (TAT) in MSI‐high cases (median TAT: 24 days) was a critical issue that directly resulted in treatment delay. Of the 50 patients with MSI‐high tumors, 24 (48.0%) received ICIs and 34 (68.0%) were referred to the Department of Clinical Genetic Oncology where 6 (12.0%) patients were diagnosed with Lynch syndrome. Conclusions MSI testing was successfully performed for various types of tumors and specimens in clinical practice. Our study results identified certain issues associated with the clinical implementation of MSI testing, including optimal specimen selection, extended TAT in MSI‐high cases, and awareness of hereditary tumors.
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